Most prior art pliant disc systems (known commonly as floppy discs) are limited to read only operations. Such devices employ a mechanical detent system which moves a magnetic head from track to track in accordance with external commands which specify the address of recorded data. These mechanical detent systems are inherently slow, requiring in excess of 333 millisec to effect track to track transitions. What is actually desired is an arrangement for rapidly and accurately positioning a head which is capable of both reading and writing information on a cartridge type floppy dis. In addition, it is desirable that the system include a means for preventing accidental erasure of prerecorded data which is to be retained, as well as means for sensing the origin and extremity positions of head travel, and means for indexing and identifying various sectors of the disc.
Accordingly, a primary object of the present invention is to provide a read-write floppy disc system.
Another object of the present invention is to provide a screw drive stepping motor arrangement for positioning a magnetic head relative to a pliant recording medium.
Another object of the present invention is to provide a straddle erase head to effect high density recording on a pliant disc.
Another object of the present invention is to provide a non-contacting sensing arrangement for determining the various locations of the recording head relative to the recording medium.
Another object of the present invention is to provide a protective interlock to prevent recorded information from being accidentally lost.
Another object of the invention is to provide a means for identifying various sectors of the recording disc.
Other objects and advantages will be obvious from the detailed description of a preferred embodiment given herein below.